1. Field of the Invention
The present invention relates to an improvement in a disc brake for a vehicle.
2. Description of the Related Art:
Pads which are employed for a disk brake must endure high surface pressure, heavy loads and high temperatures and are therefore formed from materials that have high wear resistance and good heat resistance.
Accordingly, it has heretofore been common practice to employ asbestos-resin molded materials which are formed by employing asbestos as a base material and mixing it with a binder resin and various kinds of friction adjustors. However, semimetallic and metallic materials using metal wires as a basic material have recently been employed to reduce dust pollution and extend the life of such pads.
Metallic pads formed by using semimetallic or metallic materials as a base material suffer, however, from the following problems. Since the disc is also formed from a metallic material, when the disc and the pads come into contact with each other, sparks are generated. If these sparks adhere to the piston boot or pin boots of the disc brake, the piston or pin boots may be burned and deteriorated, which will result in breakage.